/*
 * Copyright 2002-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.validation;

import java.util.Map;

import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * Convenience methods for looking up BindingResults in a model Map.
 *
 * @author Juergen Hoeller
 * @see BindingResult#MODEL_KEY_PREFIX
 * @since 2.0
 */
public abstract class BindingResultUtils {

    /**
     * Find the BindingResult for the given name in the given model.
     *
     * @param model the model to search
     * @param name  the name of the target object to find a BindingResult for
     * @return the BindingResult, or {@code null} if none found
     * @throws IllegalStateException if the attribute found is not of type BindingResult
     */
    @Nullable
    public static BindingResult getBindingResult(Map<?, ?> model, String name) {
        Assert.notNull(model, "Model map must not be null");
        Assert.notNull(name, "Name must not be null");
        Object attr = model.get(BindingResult.MODEL_KEY_PREFIX + name);
        if (attr != null && !(attr instanceof BindingResult)) {
            throw new IllegalStateException("BindingResult attribute is not of type BindingResult: " + attr);
        }
        return (BindingResult) attr;
    }

    /**
     * Find a required BindingResult for the given name in the given model.
     *
     * @param model the model to search
     * @param name  the name of the target object to find a BindingResult for
     * @return the BindingResult (never {@code null})
     * @throws IllegalStateException if no BindingResult found
     */
    public static BindingResult getRequiredBindingResult(Map<?, ?> model, String name) {
        BindingResult bindingResult = getBindingResult(model, name);
        if (bindingResult == null) {
            throw new IllegalStateException("No BindingResult attribute found for name '" + name +
                    "'- have you exposed the correct model?");
        }
        return bindingResult;
    }

}
